RESUMEN
Seventeen infants under one year of age admitted to the Emergency Service of the General Hospital of the Medical Center La Raza during the year 1976 were included in this study with the diagnosis of salicylate poisoning. Determination of plasma salicylate by the ultrafiltrate method was practiced to all patients. A direct relationship between total plasmatic salicylate and its free fraction was found together with an inverse proportion between percentage of total free--salicylate and plasma pH and a lineal correlation between plasma free--salicylate and salicylate obtained in spinal fluid. It is concluded that determination of the free fraction of plasma salicylate is an easy diagnostic method for the better evaluation of salicylate acid poisoning in the infant.